drivers/acpi/acpica/utmath.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: utmath - Integer math support routines
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46
  47 #define _COMPONENT          ACPI_UTILITIES
  48 ACPI_MODULE_NAME("utmath")
  49
  50 /* Structures used only for 64-bit divide */
  51 typedef struct uint64_struct {
  52         u32 lo;
  53         u32 hi;
  54
  55 } uint64_struct;
  56
  57 typedef union uint64_overlay {
  58         u64 full;
  59         struct uint64_struct part;
  60
  61 } uint64_overlay;
  62
  63 /*
  64  * Optional support for 64-bit double-precision integer multiply and shift.
  65  * This code is configurable and is implemented in order to support 32-bit
  66  * kernel environments where a 64-bit double-precision math library is not
  67  * available.
  68  */
  69 #ifndef ACPI_USE_NATIVE_MATH64
  70
  71 /*******************************************************************************
  72  *
  73  * FUNCTION:    acpi_ut_short_multiply
  74  *
  75  * PARAMETERS:  multiplicand        - 64-bit multiplicand
  76  *              multiplier          - 32-bit multiplier
  77  *              out_product         - Pointer to where the product is returned
  78  *
  79  * DESCRIPTION: Perform a short multiply.
  80  *
  81  ******************************************************************************/
  82
  83 acpi_status
  84 acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product)
  85 {
  86         union uint64_overlay multiplicand_ovl;
  87         union uint64_overlay product;
  88         u32 carry32;
  89
  90         ACPI_FUNCTION_TRACE(ut_short_multiply);
  91
  92         multiplicand_ovl.full = multiplicand;
  93
  94         /*
  95          * The Product is 64 bits, the carry is always 32 bits,
  96          * and is generated by the second multiply.
  97          */
  98         ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.hi, multiplier,
  99                           product.part.hi, carry32);
 100
 101         ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.lo, multiplier,
 102                           product.part.lo, carry32);
 103
 104         product.part.hi += carry32;
 105
 106         /* Return only what was requested */
 107
 108         if (out_product) {
 109                 *out_product = product.full;
 110         }
 111
 112         return_ACPI_STATUS(AE_OK);
 113 }
 114
 115 /*******************************************************************************
 116  *
 117  * FUNCTION:    acpi_ut_short_shift_left
 118  *
 119  * PARAMETERS:  operand             - 64-bit shift operand
 120  *              count               - 32-bit shift count
 121  *              out_result          - Pointer to where the result is returned
 122  *
 123  * DESCRIPTION: Perform a short left shift.
 124  *
 125  ******************************************************************************/
 126
 127 acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result)
 128 {
 129         union uint64_overlay operand_ovl;
 130
 131         ACPI_FUNCTION_TRACE(ut_short_shift_left);
 132
 133         operand_ovl.full = operand;
 134
 135         if ((count & 63) >= 32) {
 136                 operand_ovl.part.hi = operand_ovl.part.lo;
 137                 operand_ovl.part.lo = 0;
 138                 count = (count & 63) - 32;
 139         }
 140         ACPI_SHIFT_LEFT_64_BY_32(operand_ovl.part.hi,
 141                                  operand_ovl.part.lo, count);
 142
 143         /* Return only what was requested */
 144
 145         if (out_result) {
 146                 *out_result = operand_ovl.full;
 147         }
 148
 149         return_ACPI_STATUS(AE_OK);
 150 }
 151
 152 /*******************************************************************************
 153  *
 154  * FUNCTION:    acpi_ut_short_shift_right
 155  *
 156  * PARAMETERS:  operand             - 64-bit shift operand
 157  *              count               - 32-bit shift count
 158  *              out_result          - Pointer to where the result is returned
 159  *
 160  * DESCRIPTION: Perform a short right shift.
 161  *
 162  ******************************************************************************/
 163
 164 acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result)
 165 {
 166         union uint64_overlay operand_ovl;
 167
 168         ACPI_FUNCTION_TRACE(ut_short_shift_right);
 169
 170         operand_ovl.full = operand;
 171
 172         if ((count & 63) >= 32) {
 173                 operand_ovl.part.lo = operand_ovl.part.hi;
 174                 operand_ovl.part.hi = 0;
 175                 count = (count & 63) - 32;
 176         }
 177         ACPI_SHIFT_RIGHT_64_BY_32(operand_ovl.part.hi,
 178                                   operand_ovl.part.lo, count);
 179
 180         /* Return only what was requested */
 181
 182         if (out_result) {
 183                 *out_result = operand_ovl.full;
 184         }
 185
 186         return_ACPI_STATUS(AE_OK);
 187 }
 188 #else
 189
 190 /*******************************************************************************
 191  *
 192  * FUNCTION:    acpi_ut_short_multiply
 193  *
 194  * PARAMETERS:  See function headers above
 195  *
 196  * DESCRIPTION: Native version of the ut_short_multiply function.
 197  *
 198  ******************************************************************************/
 199
 200 acpi_status
 201 acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product)
 202 {
 203
 204         ACPI_FUNCTION_TRACE(ut_short_multiply);
 205
 206         /* Return only what was requested */
 207
 208         if (out_product) {
 209                 *out_product = multiplicand * multiplier;
 210         }
 211
 212         return_ACPI_STATUS(AE_OK);
 213 }
 214
 215 /*******************************************************************************
 216  *
 217  * FUNCTION:    acpi_ut_short_shift_left
 218  *
 219  * PARAMETERS:  See function headers above
 220  *
 221  * DESCRIPTION: Native version of the ut_short_shift_left function.
 222  *
 223  ******************************************************************************/
 224
 225 acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result)
 226 {
 227
 228         ACPI_FUNCTION_TRACE(ut_short_shift_left);
 229
 230         /* Return only what was requested */
 231
 232         if (out_result) {
 233                 *out_result = operand << count;
 234         }
 235
 236         return_ACPI_STATUS(AE_OK);
 237 }
 238
 239 /*******************************************************************************
 240  *
 241  * FUNCTION:    acpi_ut_short_shift_right
 242  *
 243  * PARAMETERS:  See function headers above
 244  *
 245  * DESCRIPTION: Native version of the ut_short_shift_right function.
 246  *
 247  ******************************************************************************/
 248
 249 acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result)
 250 {
 251
 252         ACPI_FUNCTION_TRACE(ut_short_shift_right);
 253
 254         /* Return only what was requested */
 255
 256         if (out_result) {
 257                 *out_result = operand >> count;
 258         }
 259
 260         return_ACPI_STATUS(AE_OK);
 261 }
 262 #endif
 263
 264 /*
 265  * Optional support for 64-bit double-precision integer divide. This code
 266  * is configurable and is implemented in order to support 32-bit kernel
 267  * environments where a 64-bit double-precision math library is not available.
 268  *
 269  * Support for a more normal 64-bit divide/modulo (with check for a divide-
 270  * by-zero) appears after this optional section of code.
 271  */
 272 #ifndef ACPI_USE_NATIVE_DIVIDE
 273
 274 /*******************************************************************************
 275  *
 276  * FUNCTION:    acpi_ut_short_divide
 277  *
 278  * PARAMETERS:  dividend            - 64-bit dividend
 279  *              divisor             - 32-bit divisor
 280  *              out_quotient        - Pointer to where the quotient is returned
 281  *              out_remainder       - Pointer to where the remainder is returned
 282  *
 283  * RETURN:      Status (Checks for divide-by-zero)
 284  *
 285  * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
 286  *              divide and modulo. The result is a 64-bit quotient and a
 287  *              32-bit remainder.
 288  *
 289  ******************************************************************************/
 290
 291 acpi_status
 292 acpi_ut_short_divide(u64 dividend,
 293                      u32 divisor, u64 *out_quotient, u32 *out_remainder)
 294 {
 295         union uint64_overlay dividend_ovl;
 296         union uint64_overlay quotient;
 297         u32 remainder32;
 298
 299         ACPI_FUNCTION_TRACE(ut_short_divide);
 300
 301         /* Always check for a zero divisor */
 302
 303         if (divisor == 0) {
 304                 ACPI_ERROR((AE_INFO, "Divide by zero"));
 305                 return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
 306         }
 307
 308         dividend_ovl.full = dividend;
 309
 310         /*
 311          * The quotient is 64 bits, the remainder is always 32 bits,
 312          * and is generated by the second divide.
 313          */
 314         ACPI_DIV_64_BY_32(0, dividend_ovl.part.hi, divisor,
 315                           quotient.part.hi, remainder32);
 316
 317         ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor,
 318                           quotient.part.lo, remainder32);
 319
 320         /* Return only what was requested */
 321
 322         if (out_quotient) {
 323                 *out_quotient = quotient.full;
 324         }
 325         if (out_remainder) {
 326                 *out_remainder = remainder32;
 327         }
 328
 329         return_ACPI_STATUS(AE_OK);
 330 }
 331
 332 /*******************************************************************************
 333  *
 334  * FUNCTION:    acpi_ut_divide
 335  *
 336  * PARAMETERS:  in_dividend         - Dividend
 337  *              in_divisor          - Divisor
 338  *              out_quotient        - Pointer to where the quotient is returned
 339  *              out_remainder       - Pointer to where the remainder is returned
 340  *
 341  * RETURN:      Status (Checks for divide-by-zero)
 342  *
 343  * DESCRIPTION: Perform a divide and modulo.
 344  *
 345  ******************************************************************************/
 346
 347 acpi_status
 348 acpi_ut_divide(u64 in_dividend,
 349                u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
 350 {
 351         union uint64_overlay dividend;
 352         union uint64_overlay divisor;
 353         union uint64_overlay quotient;
 354         union uint64_overlay remainder;
 355         union uint64_overlay normalized_dividend;
 356         union uint64_overlay normalized_divisor;
 357         u32 partial1;
 358         union uint64_overlay partial2;
 359         union uint64_overlay partial3;
 360
 361         ACPI_FUNCTION_TRACE(ut_divide);
 362
 363         /* Always check for a zero divisor */
 364
 365         if (in_divisor == 0) {
 366                 ACPI_ERROR((AE_INFO, "Divide by zero"));
 367                 return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
 368         }
 369
 370         divisor.full = in_divisor;
 371         dividend.full = in_dividend;
 372         if (divisor.part.hi == 0) {
 373                 /*
 374                  * 1) Simplest case is where the divisor is 32 bits, we can
 375                  * just do two divides
 376                  */
 377                 remainder.part.hi = 0;
 378
 379                 /*
 380                  * The quotient is 64 bits, the remainder is always 32 bits,
 381                  * and is generated by the second divide.
 382                  */
 383                 ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo,
 384                                   quotient.part.hi, partial1);
 385
 386                 ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo,
 387                                   quotient.part.lo, remainder.part.lo);
 388         }
 389
 390         else {
 391                 /*
 392                  * 2) The general case where the divisor is a full 64 bits
 393                  * is more difficult
 394                  */
 395                 quotient.part.hi = 0;
 396                 normalized_dividend = dividend;
 397                 normalized_divisor = divisor;
 398
 399                 /* Normalize the operands (shift until the divisor is < 32 bits) */
 400
 401                 do {
 402                         ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
 403                                             normalized_divisor.part.lo);
 404                         ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
 405                                             normalized_dividend.part.lo);
 406
 407                 } while (normalized_divisor.part.hi != 0);
 408
 409                 /* Partial divide */
 410
 411                 ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
 412                                   normalized_dividend.part.lo,
 413                                   normalized_divisor.part.lo, quotient.part.lo,
 414                                   partial1);
 415
 416                 /*
 417                  * The quotient is always 32 bits, and simply requires
 418                  * adjustment. The 64-bit remainder must be generated.
 419                  */
 420                 partial1 = quotient.part.lo * divisor.part.hi;
 421                 partial2.full = (u64) quotient.part.lo * divisor.part.lo;
 422                 partial3.full = (u64) partial2.part.hi + partial1;
 423
 424                 remainder.part.hi = partial3.part.lo;
 425                 remainder.part.lo = partial2.part.lo;
 426
 427                 if (partial3.part.hi == 0) {
 428                         if (partial3.part.lo >= dividend.part.hi) {
 429                                 if (partial3.part.lo == dividend.part.hi) {
 430                                         if (partial2.part.lo > dividend.part.lo) {
 431                                                 quotient.part.lo--;
 432                                                 remainder.full -= divisor.full;
 433                                         }
 434                                 } else {
 435                                         quotient.part.lo--;
 436                                         remainder.full -= divisor.full;
 437                                 }
 438                         }
 439
 440                         remainder.full = remainder.full - dividend.full;
 441                         remainder.part.hi = (u32)-((s32)remainder.part.hi);
 442                         remainder.part.lo = (u32)-((s32)remainder.part.lo);
 443
 444                         if (remainder.part.lo) {
 445                                 remainder.part.hi--;
 446                         }
 447                 }
 448         }
 449
 450         /* Return only what was requested */
 451
 452         if (out_quotient) {
 453                 *out_quotient = quotient.full;
 454         }
 455         if (out_remainder) {
 456                 *out_remainder = remainder.full;
 457         }
 458
 459         return_ACPI_STATUS(AE_OK);
 460 }
 461
 462 #else
 463
 464 /*******************************************************************************
 465  *
 466  * FUNCTION:    acpi_ut_short_divide, acpi_ut_divide
 467  *
 468  * PARAMETERS:  See function headers above
 469  *
 470  * DESCRIPTION: Native versions of the ut_divide functions. Use these if either
 471  *              1) The target is a 64-bit platform and therefore 64-bit
 472  *                 integer math is supported directly by the machine.
 473  *              2) The target is a 32-bit or 16-bit platform, and the
 474  *                 double-precision integer math library is available to
 475  *                 perform the divide.
 476  *
 477  ******************************************************************************/
 478
 479 acpi_status
 480 acpi_ut_short_divide(u64 in_dividend,
 481                      u32 divisor, u64 *out_quotient, u32 *out_remainder)
 482 {
 483
 484         ACPI_FUNCTION_TRACE(ut_short_divide);
 485
 486         /* Always check for a zero divisor */
 487
 488         if (divisor == 0) {
 489                 ACPI_ERROR((AE_INFO, "Divide by zero"));
 490                 return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
 491         }
 492
 493         /* Return only what was requested */
 494
 495         if (out_quotient) {
 496                 *out_quotient = in_dividend / divisor;
 497         }
 498         if (out_remainder) {
 499                 *out_remainder = (u32) (in_dividend % divisor);
 500         }
 501
 502         return_ACPI_STATUS(AE_OK);
 503 }
 504
 505 acpi_status
 506 acpi_ut_divide(u64 in_dividend,
 507                u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
 508 {
 509         ACPI_FUNCTION_TRACE(ut_divide);
 510
 511         /* Always check for a zero divisor */
 512
 513         if (in_divisor == 0) {
 514                 ACPI_ERROR((AE_INFO, "Divide by zero"));
 515                 return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
 516         }
 517
 518         /* Return only what was requested */
 519
 520         if (out_quotient) {
 521                 *out_quotient = in_dividend / in_divisor;
 522         }
 523         if (out_remainder) {
 524                 *out_remainder = in_dividend % in_divisor;
 525         }
 526
 527         return_ACPI_STATUS(AE_OK);
 528 }
 529
 530 #endif